Since October 1991, the U.K. Meteorlogical Office has used the technique of data assimilation to produce global meteorological analyses of the troposphere and stratosphere. These analyses are constructed from conventional meteorological measurements in the troposphere and lower stratosphere, temperature soundings from NOAA polar-orbiting satellites. The analyses show very clear quasi-biennial and semi-annual oscillation in equatorial winds. The quasi-biennial oscillation has its maximum amplitude of about 20 ms-1 near 30 hPa, and exhibits descending easterly and westerly shear zones. Analyzed winds compare well with radiosonde observations in the lower stratosphere. The semi-annual oscillation has its peak amplitude of about 30 ms-1 near the stratopause. Winds near the equatorial stratopause show strong longitudinal variations on a planetary scale during both the westerly and easterly phases of the semi-annual oscillation. ¿ American Geophysical Union 1994